No experience with it, so I just read some online stuff. Confusing "logic" to me.

It seems wasteful to vent any air to the outside. If the basement air is heated, that's certainly costly. And if it's cold down there, the air humidity is probably low in the winter anyway, even if you have moisture in the walls, which is a separate issue. In winter, your warm interior air contains more moisture than cold exterior air, but you actually want that moisture in the air. But you also don't want that interior air getting inside finished basement walls, especially ones with cold foundation walls behind. Then the moisture condenses on the cold wall (in the wall) and you eventually get that moldy smell, etc.

So you want to seal out the warm interior air from the wall cavity. And also figure a way to get the walls themselves to air out if they're moist inside for other reasons.

BTw, since they sell mainly based on testimonials, I'd say be a bit skeptical. Just an observation.

In the summer months, I'd just run a humidifier. Again, if the wall cavities are moist for some reason, that may require another solution. But a regular humidifier would help. Incidentally, check and make sure the rim joist area is sealed up well.

The answer in brief: NO, it does not work and can't work! Just think about the basic concept: the Humidex model is nothing more than a little exhaust fan installed into the outside wall. It just extracts air from your room to the outside, drawing more moist air form further away (other rooms, perhaps other floor levels). Compared to a real dehumidifier, it does not extract moisture which then collects in a tank, but just moves air!
The Humidex website and printed claims are definitely misleading the customer. Here is an excerpt of the 10 year warranty: "As it takes a significant time to reduce moisture content of various building material (i.e. concrete, drywall, furniture, etc.) in the area serviced by your Humidex, it must be allowed to operate through a complete seasonal cycle to fully appreciate the effectiveness and benefit provided." Should the customer wait for 6 months (i.e. a summer season)? Since when does furniture have a moisture content?
I feel stupid not seeing the technological hoax before installation. I have started remedial actions against the company which sold me the unit (WAVE Home Solutions) and the installer (Pure Air Systems).

Not much better than opening a window.

Dr. Lstiburek of Building Science Corp., often described as the leading expert on moisture in buildings in North America, describes thethree recommended ways to provide supplemental dehumidification for a home: stand alone dehumidifiers; ventilating dehumidifiers and enhanced air-conditioning systems.

He must have missed the miracles of Humidex.

"Again basement windows are at the Top of the basement. Where does heat go?"

And if you opemn a window the outside aiur somces in.

If you suck the air out of the room and blow outside where do you think the replacemenrt air comes from?

Either outside or the rest of the house, and it is then replaced from the outside.

It is a great way to run up your heating and cooling bills.

Get a dehumidifier and plug it in.

I prefer ones with a drain hose that can be routed to a floor drain or a condensate pump.
This eliminates the tank dumping.

It's amazing how forum monitoring software immediately brings in the corporate/salespersons of the systems in question. (Check the poster registration dates.) It would be more honest if they would identify themselves as such.

Using basement exhaust fans creates a negative pressure; supply air is ultimately drawn in from the outside creating more work for your a/c system. That's why it's cheaper to run a dehumidifier or enhanced a/c and presumably why Building Science Corp. recommends those approaches.

Worthy, it isn't cheaper to run a dehumidifier! Those fans I cobble together are 18W and cost $7. Drier air costs less to heat OR cool.

The question is, do they really dehumidify? And that is as simple to prove as buying a humidity meter.

How hard is it to understand that air separates by gravity? Heavy disgusting air sinks to the floor. Get rid of it! You would rather let it fill the room and breathe it?

Humidex product does not work. Save your money and purchase a dehumidifier

Humidex makes a good product, but you can do so much better with a unit that uses the same principle, is at least the same quality, and sells for much less (nearly half the price), the Breeze DL. We have had one in our basement for almost 10 years. The entry level Breeze (single fan) has been selling on Ebay and Amazon for over 10 years. The Breeze is made of a sturdy plastic, so it doesn't rust or dent. Has no computer parts, which aren't recommended in humid areas, and is backed by a no-questions-asked 5-year warranty and full tech support. It's quiet, takes less space than a Humidex, and can be customized by the seller. It installs by using a simple dryer vent hook up, so it's a DIY project. Also, the Breeze is made by an American company, unlike Humidex. Check it out by searching for Breeze Systems International. You'll be glad you did.

Humidex makes a good product, but you can do so much better with a unit that uses the same principle, is at least the same quality, and sells for much less (nearly half the price), the Breeze DL. We have had one in our basement for almost 10 years. The entry level Breeze (single fan) has been selling on Ebay and Amazon for over 10 years. The Breeze is made of a sturdy plastic, so it doesn't rust or dent. Has no computer parts, which aren't recommended in humid areas, and is backed by a no-questions-asked 5-year warranty and full tech support. It's quiet, takes less space than a Humidex, and can be customized by the seller. It installs by using a simple dryer vent hook up, so it's a DIY project. Also, the Breeze is made by an American company, unlike Humidex. Check it out by searching for Breeze Systems International. You'll be glad you did.

I take it all back. I have no idea how air, water vapor, water droplets, any of it works. Moist air is now supposedly good for your lungs and bad for storing things. It is all about the dew point. See dpcalc.org

In both houses that I’ve owned for over 20 years, the humidex has been FABULOUS. I would never own a home with a basement without one installed.